I have a 98 Lumina 3.1 sedan with 110,000 miles. It has been running rough at low speeds and in idle, has the P0300 misfire code indicating a random/multiple missfire, and has also been a little sluggish under any condition. I had a full tune-up performed by a professional and it did nothing to help. Parts replaced include plugs, wires, pcv valve, air filter, and fuel filter.
This may be a separate issue as it started occuring after the missfire. But my radio is also shutting off and powering on every once in while by itself. It never looses the time, so I'm thinking that is indicative of either a bad accessory wire, or a bad iginition switch. Could this be related?